This invention relates generally to boat lifts and more particularly to an improved clamp mechanism for an adjustable torsion bar which forms part of a boat lift frame.
It is common practice for the frames of boat lifts to include torsion bars which extend transversely across the boat lift and provide side to side leveling. In order to accommodate boats having different widths and docks that vary in width, the torsion bars must be constructed to adjust in their length. The length adjustment is typically provided by a telescopic construction of the torsion bar in which one tube fits telescopically inside of another larger tube.
In the past, the torsion bar has been locked at the desired length by splitting the larger tube at three corners, thus providing tabs on the larger tube which may be clamped onto the smaller tube. In this manner, the tubes can be locked against telescopic extension and retraction and the clamp can be released when it is desired to adjust the length of the torsion bar. The main problem with this type of arrangement is that the tabs are susceptible to breakage, especially after the boat lift has been in service for an extended period. If the tabs break, the clamp loses holding power and the tubes can slip and cause the boat lift to lean unacceptably.
The present invention is directed to an improved clamp mechanism for clamping together the telescopic tubes of a torsion bar for a boat lift. The invention is characterized by the ability to reliably clamp the tubes together in a manner to avoid slippage and the problems that result when the tubes slip.
In accordance with the invention, the larger and smaller telescoping square tubes of a boat lift frame are clamped together by a pair of opposing angle members which are applied to the tubes adjacent to the area where the tubes meet. The inside faces of the flanges of the angle members are provided at one end with plates which fit against the sides of the smaller square tube. The opposite ends of the flanges directly engage the sides of the larger tube. Consequently, the angles can be clamped together in opposition to one another so that the tubes are locked together and prevented from slipping relative to one another.
The clamping function is provided by nut and bolt assemblies which connect U-shaped lugs that project from the angle members. Each lug is located to align with a lug on the opposing angle member so that when the nuts are tightened on the bolts, the lugs are pulled together to thus draw the angles inwardly and clamp them securely onto the tubes. The plates which line the inside faces of parts of the flanges compensate for the size difference between the larger and smaller tubes.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.